Mirror device with visual indicator to enable identification of highly-reflective region to ensure correct orientation of the same when disposed in an optical subassembly

Abstract

A mirror device for use in an optical subassembly is disclosed that includes at least one surface with a visible indicator to allow a technician to differentiate a highly-reflective surface from relatively less reflective (e.g., un-coated) surfaces. The mirror device may be formed using known approaches, such as through the deposition of a metallic material on to a surface of the mirror device followed by one or more optional coating layers. Before, or after, forming the highly-reflective surface, a visual indicator may be introduced on to a surface of the mirror device that is opposite the highly-reflective surface. The visual indicator may comprise, for example, random scratches/scoring etched from a wire brush or tool, paint, epoxy, ink, or any other indicator that allows a technician to visually differentiate the portion of the mirror device having the visual indicator from the highly-reflective portion.

What is claimed is: 
     
       1. A mirror device for use in an optical subassembly module, the mirror device comprising:
 an opaque base portion providing a first surface opposite a second surface; 
 a layer of metallic material disposed on the first surface of the base portion to provide a highly-reflective surface to reflect at least a portion of incident channel wavelengths; and 
 a visual indicator disposed on the second surface of the base portion to indicate a position of the highly-reflective surface, wherein the visual indicator comprises a plurality of random scratches disposed on the second surface. 
 
     
     
       2. The mirror device of  claim 1 , wherein the highly-reflective surface has a reflectivity of at least 98% percent for associated channel wavelengths. 
     
     
       3. The mirror device of  claim 1 , wherein the visual indicator causes the second surface to have an overall reflectivity that is less than the overall reflectivity of the highly-reflective surface. 
     
     
       4. The mirror device of  claim 1 , wherein the visual indicator comprises a primary marking and a second marking, the primary marking indicating a type of material forming the layer of metallic material and the second marking indicating whether a coating layer is disposed on the layer of metallic material. 
     
     
       5. The mirror device of  claim 1 , wherein the primary marking comprises a symbol. 
     
     
       6. The mirror device of  claim 1 , wherein the layer of metallic material comprises Silver (Ag), Gold (Au), Aluminum (Al), or an alloy thereof. 
     
     
       7. The mirror device of  claim 1 , wherein the highly reflective surface reflects 98% or more of incident channel wavelengths. 
     
     
       8. A method comprising:
 depositing a metal layer on to a first surface of a mirror device to provide a highly-reflective surface; 
 depositing a visual indicator on to a second surface of the mirror device, the second surface being opposite the first surface, the visual indicator indicating a position of the highly-reflective surface, wherein depositing a visual indicator on to the second surface of the mirror device further comprises scuffing the second surface to etch random scratches into the second surface; 
 inserting the mirror device into a mirror holder; and 
 disposing the mirror holder in an optical subassembly housing, the second surface of the mirror device facing the mirror holder and the first surface being disposed facing a light path within the optical subassembly housing. 
 
     
     
       9. The method of  claim 8 , wherein depositing the metal layer further includes depositing a metal layer comprising Silver (Ag), Gold (Au), or Aluminum (Al) on to the first surface. 
     
     
       10. The method of  claim 9 , further comprising depositing a protective coating layer on to the metal layer. 
     
     
       11. The method of  claim 10 , wherein the second surface of the mirror device faces away from the light path within the optical subassembly housing. 
     
     
       12. The method of  claim 8 , wherein depositing a visual indicator on to the second surface of the mirror device further comprises depositing a symbol on to the second surface. 
     
     
       13. A multi-channel receiver optical subassembly (ROSA) including a plurality of photodiode packages, the ROSA comprising:
 a housing including at least first and second sidewalls on opposite sides of the housing and extending along a longitudinal axis from a first end to a second end, and forming a compartment defined by an inner surface therein; 
 a mirror holder comprising a plurality of mirror devices, each mirror device comprising:
 a base portion providing a first surface opposite a second surface; 
 a layer of metallic material disposed on the first surface of the base portion to provide a highly-reflective surface to reflect at least a portion of incident channel wavelengths; 
 a visual indicator disposed on the second surface of the base portion to indicate a position of the highly-reflective surface, wherein the visual indicator comprises a plurality of random scratches disposed on the second surface; 
 and wherein the second surface faces the mirror holder and faces away from the plurality of photodiode packages. 
 
 
     
     
       14. The multi-channel ROSA of  claim 13 , wherein the highly-reflective surface of each mirror device has a reflectivity of at least 98% percent for associated channel wavelengths. 
     
     
       15. The multi-channel ROSA of  claim 13 , wherein the visual indicator of each mirror device causes the second surface to have an overall reflectivity that is less than the overall reflectivity of the highly-reflective surface. 
     
     
       16. The multi-channel ROSA of  claim 13 , wherein the visual indicator of each mirror device comprises a primary marking and a second marking, the primary marking indicating a type of material forming the layer of metallic material and the second marking indicating whether a coating layer is disposed on the layer of metallic material.